Advances in semiconductor device fabrication processes have been driven by, amongst other things, the need to produce increasingly powerful electronic devices while adhering to stringent power consumption requirements. Reductions in the device feature sizes that characterize these fabrication processes drives the creation of these electronic devices by increasing, for example, the component or transistor density of the integrated circuits that are used to construct such devices. Such increases in component density, however, can come at the cost of increased power dissipation, such as caused by component leakage or by the increased functionality that may be built into a given integrated circuit. Such increases in power dissipation may make it difficult to design electronic devices that adhere to a specified set, or class, of power consumption requirements. This limitation can be overcome by building electronic devices, or fabricating electronic circuits, that incorporate one or more power gating techniques.
Power gating can reduce the amount of power consumed in a circuit by creating a gated power rail that can be disconnected from a power supply to cut off current to one or more sub-circuits, such as during periods when the functionally provided by such sub-circuits is not needed. Reconnecting a gated power rail to a power supply can generate current spikes which can cause reliability problems in some electronic devices. Techniques for limiting these current spikes can require the addition of complicated circuitry to devices that incorporate power gating, such as for generating voltage references or biasing comparator circuits.
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.